The mission of the OHSU Cancer Institute Transgenic/Gene Targeting Shared Resource is to provide Cancer Institute investigators with the highest quality assistance in the development of genetically modified mouse models for the study of human cancer. The specific services provided by this SR in the area of mouse embryology and transgenesis are: 1) transgene microinjection, 2) embryonic stem (ES) cell transfection, and clonal selection, 3) blastocyst injection of embryonic stem cells, and 4) rederivation of pathogen-positive mouse strains. Usage of this SR over the past six years has been substantial: 55 investigators, including 27 OCI members (49%), initiated projects for the development of genetically manipulated mouse models. During this period, a total of 270 projects were completed; the numbers by individual project types are: transgene microinjections: 121; ES cells; 89; blastocyst injection: 41; strain rederivation: 19. Thus far, mouse models developed by OCI investigators with the assistance of this Shared Resource directly yielded 18 peer-reviewed publications, many in high profile journals. The Transgenic SR is in the process of further expanding its line of services to include mouse strain protection by sperm cryopreservation, which is set up with funding from the Oregon Opportunity Initiative, as well as transgenic mouse production using lentivirus vectors.